Air pump



FIG. 1 is a perspective view of an air pump showing the claimed design;

FIG. 2 is another perspective view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a front elevational view thereof; and,

FIG. 8 is a left side view thereof.

The broken lines illustrate portions of the air pump that form no part of the claimed design. 

CLAIM The ornamental design for an air pump, as shown and described. 